This Giant Asteroid Left a Bigger Impact Than the One That Killed the Dinosaurs

The 10-kilometer-wide asteroid that slammed into Earth and took out the dinosaurs 65 million years ago was cataclysmic. But now there's evidence that an even bigger asteroid barreled into Earth billions of years earlier — and the damage was downright apocalyptic.

This giant asteroid was probably 20 to 30 kilometers wide and hit Earth about 3.46 billion years ago, according to new research published in the journal Precambrian Research.

"The impact would have triggered earthquakes orders of magnitude greater than terrestrial earthquakes, it would have caused huge tsunamis and would have made cliffs crumble," Andrew Glikson, a scientist at the Australian National University Planetary Institute who worked on the research, said in a statement.

Where's the evidence? There's no enormous impact crater that we somehow missed for thousands of years. Instead, Glikson and his team are basing their claim on tiny glass beads called spherules found in western Australia. Spherules form when material gets vaporized in an asteroid impact.

But even though scientists have found evidence of the impact, they have no idea where the asteroid struck.

"Material from the impact would have spread worldwide," Glikson explained. Scientists can't find any evidence of a huge impact crater because billions of years' worth of volcanic eruptions and tectonic plate shifts have covered it up.

Follow-up tests on the samples from Australia seemed to back up the researchers' claim that this is evidence of an asteroid strike. The tests revealed traces of platinum, nickel and chromium, which are also elements found in asteroids.

A gold mine of asteroid impacts: Astronomers and planetary scientists suspect Earth had a very violent past. When it was first forming, it was likely pummeled with asteroids. That means there could have been a lot more of these asteroid impacts that we don't know about yet.

"This is just the tip of the iceberg," Glikson said. "We've only found evidence for 17 impacts older than 2.5 billion years, but there could have been hundreds."